1. Field of the Invention
This invention relates generally to semiconductor fabrication and, more particularly, to forming titanium silicon nitride films.
2. Description of the Related Art
Integrated circuits or other semiconductor devices can include metal features formed in a dielectric material. Over time, the metal can diffuse into the dielectric. This is undesirable for, among other things, device reliability. Diffusion barriers are typically provided between the metal and the dielectric to prevent this metal diffusion.
Titanium nitride (TiN) has been used as a diffusion barrier. However, TiN can still permit some diffusion of metals across a TiN layer. It is believed that the diffusion occurs because of the crystal structure of the TiN layers; metals can diffusion along grain boundaries in the TiN layer.
More amorphous materials or nano-crystalline materials, having very small grains, may provide a more effective barrier against diffusion. Titanium silicon nitride (TiSiN) has been explored as one such material.
Accordingly, research into the development of TiSiN deposition processes is on-going and there is a continuing need for methods for forming TiSiN with desired material properties.